The present invention relates to a semiconductor laser device. Particularly, the present invention relates to a semiconductor laser device used as an optical pickup apparatus which reads out information recorded in an optical recording medium or writes information in the optical recording medium.
As a conventional semiconductor laser device, Japanese Laid-open patent publication No. 2001-111159 describes a semiconductor laser device 104 as shown in FIG. 9. In a housing portion of an insulative frame 100 with an upper end opened, a semiconductor laser element 101, a reflection mirror 102, a light acceptance unit 103 and so on are housed. The insulative frame 100 is made of PPS resin having a heat-resisting temperature of 260° C. However, in a fabrication process, high heat resistance is required when heating wire bond or soldering the semiconductor laser device by lead free solder. The conventional PPS resin has a disadvantage that a margin of the heat resistance is not enough.
Also, in the conventional semiconductor unit 104, when providing leads 105 on the insulative frame 100, the end 105a of each lead 105 is pressed on the bottom of the housing portion from upward to fix the lead 105. However, there has been a disadvantage that skew or shift of the lead 105 is caused when fixing the lead 105, resulting in decrease of reliability of the wire bond and deterioration of dimensional and positioning accuracy as a product of semiconductor laser device.
There has been an another disadvantage that as the insulative fame 100 of the conventional semiconductor laser device 104 has thin thickness as compared to the longitudinal dimension of the frame 100, the frame 100 deforms when the temperature is elevated. Also, there has been a disadvantage that the mechanical strength is low even at a normal temperature.
In the conventional semiconductor laser device 104, light emitted from the semiconductor laser element 101 in a plane direction is reflected on the reflection mirror 102 and irradiated in a top surface direction. As shown in FIG. 10, when attaching the reflection mirror 102 on an inclined surface of a stem 106 formed around the semiconductor element 101, resin is applied on a reflection-mirror attaching position (inclined surface) and the reflection mirror 102 is disposed and fixed thereon. In this method, however, the movement of the reflection mirror 102 is not restrained when fixing the reflection mirror 102. Therefore, there has been a disadvantage that the reflection mirror 102 is shifted, generating lift or skew and causing deterioration of fabrication accuracy or product properties.
Furthermore, in the conventional semiconductor laser device 104, signal processing (signal detecting) of light reflected on and returned from an optical recording medium is conducted using only one light acceptance unit 103. However, as shown in FIG. 10, when fixing the reflection mirror 102, for example, if the reflection mirror 102 is inclined in a direction shown by an arrow A, a light input position on the light acceptance unit 103 for signal detecting is shifted as show in FIG. 11 in a left-right direction in the figure from a light input position P at the time of focalizing. On the other hand, if the reflection mirror 102 is inclined in a direction shown by an arrow B, the light input position is shifted as shown in FIG. 11 in an up-down direction in the figure. The shift of the light input position P is also caused by change of ambient temperature.